The present invention relates to the production of trouser closures for fly openings and, more particularly, to methods and apparatus for attaching successive trouser fly strips to a continuous slide fastener chain.
In the manufacture of trouser closures for fly openings, it has been known to feed successive fly strips to a sewing machine one after another by hand in timed relation to the automatic feed of a continuous slide fastener chain to the sewing machine. This known method is subject to human error and worker fatigue, typically causing inefficient and non-uniform attachment of the fly strips.
U.S. Pat. No. 4,362,116, discloses an apparatus in which successive fly strips are automatically supplied to a sewing machine by means of a conveyor; however, a workman's hand is still used to place the fly strips one after another on the conveyer. Further, in the apparatus according to the U.S. Pat. No. 4,362,116 successive fly strips are attached to a continuous slide fastener chain before element-free gaps are provided in the fastener chain. To provide the element-free gaps in the fastener chain after the successive fly strips have been attached thereto, not only retards the rate of production, but also enables the threads of fly strips to be frayed or otherwise damaged during the element-free gap forming operation. This fraying of such threads impairs following peripheral operations, such as threading sliders, attaching end stops and even sewing individual prospective trouser closures to trousers.
Another disadvantage of the apparatus according to U.S. Pat. No. 4,362,116, is that the successive fly strips and the fastener chains must always be fed in one and the same direction for a fixed attachment orientation. It is impossible to adjust the feeding direction of the successive fly strips with respect to the feeding direction of the fastener chain to enable production of pieces in which the individual fly strips are variously oriented as attached to the fastener chain.
The present invention represents a significant advance in the art by providing a method and apparatus for full-automatically attaching successive fly strips to a continuous slide fastener chain, irrespective of the presence of element-free gaps in the fastener chain or the desired orientation of the individual fly strips with respect to the fastener chain.